Penicillin allergy is one of the most common kinds of drug allergies. It occurs when the immune system reacts to the presence of the drug penicillin or a related form such as amoxicillin or ampicillin. Symptoms of a penicillin allergy include a rash, hives, itchy eyes and swollen lips, tongue or face (angioedema). People who believe they are having an allergic reaction to penicillin should immediately contact a physician.

In highly susceptible individuals, a penicillin allergy can also result in a potentially life threatening condition known as anaphylactic shock. This condition is characterized by difficulty breathing and lowered blood pressure. Anyone who experiences severe reactions after taking penicillin should contact 911 immediately.

A physician can use a skin test or a RAST test to safely determine whether a person is allergic to penicillin and, if so, how sensitive they are. Penicillin allergies tend to be somewhat more common in children than adults, especially in those under the age of 10. Furthermore, children frequently lose this sensitivity over a period of years. However, the danger of a penicillin allergy is such that once even a mild reaction occurs, patients are usually directed to avoid the drug for the rest of their lives.

The most effective way to treat a penicillin allergy is to completely avoid the drug type (and related drug types in some cases). This can be accomplished by working closely with a physician to ensure that alternate forms of antibiotics are used when penicillin normally would. Individuals who are highly sensitive to penicillin should wear a medical alert bracelet or necklace to inform healthcare workers of their condition in the event of an emergency.

For those individuals who do experience symptoms from a penicillin allergy, several types of drugs are available to treat the condition. Antihistamines, bronchodilators and corticosteroids can all provide relief from allergy symptoms. Epinephrine is used to treat anaphylactic shock, and physicians often recommend that highly sensitive individuals carry a shot of epinephrine with them at all times.